1. Field of the Invention
The present invention relates to optical comparison devices and more particularly to a device for generating an image of a gemstone.
2. Description of the Prior Art
The prior art includes a number of inventions for analyzing various physical characteristics of gemstones. U.S. Pat. No. 4,012,141 (Hanneman) discloses an apparatus for identifying gemstones by measuring the relative reflectance of the stone being analyzed. U.S. Pat. No. 2,960,909 (Shipley) discloses an apparatus having rotating color filters for passing a concentrated beam of light through a gemstone. A light sensitive cell in this invention measures the intensity of the light passing through the gem. Color filters are provided to measure the light transmissivity of the gemstone for various different colors of light.
U.S. Pat. No. 3,467,475 (Celio) discloses a densitometer incorporating individually controllable color filters for comparing an unknown gemstone to a standard. U.S. Pat. No. 3,539,264 (Moore) discloses an optical comparator for gemstones having a lamp and an optical system for projecting lights through a gemstone and for projecting a silhouette of the gemstone on a screen.
Other relevant prior art is disclosed in the following U.S. Pat. Nos. 3,989,379 (Eickhorst); 3,867,032 (Bruck); 3,529,895 (Pincus); 1,744,485 (Michel); 3,858,979 (Elbe); 3,944,368 (Beesley); 2,421,344 (Mass); 3,520,660 (Webb); 3,237,509 (Fielding) and 3,762,817 (Harklau).